The detergent cup in a dishwasher is built to spring open during the cycle to release the cleaning solution into the water. If the detergent cup fails, the cycle ends with dirty dishes and some wasted water. The most common reasons for cup failures are soap buildups around the cup or the jets on the dishwasher. But even a brand new dishwasher or one that's been thoroughly cleaned can experience problems with the detergent cup.
Here are two reasons other than soap buildup that your detergent cup can fail to open -- and some simple dishwasher repair suggestions.
Dishes in the Way
Look at your detergent cup to see how it actually opens. The most common types on the market either swivel open or snap open and closed with a latch. Pay attention to where the cup is located once the door shuts. For example, a snap-close cup might be positioned right against the top rack when the door is closed.
If you can't figure out where the cup will be positioned, consult your owner's manual for instructions.
Use the knowledge of where the cup is and how it opens to move any dishes that might get in its way. This might include leaving the front part of the upper or lower rack empty or making sure there's nothing too tall in the front.
But you might need to worry about more than blocking the detergent cup door. Most detergent cups are triggered by the water level inside the dishwasher. Once the water starts spraying to a certain height, the detergent cup opens and the detergent is properly distributed. But if the water is blocked, this process can't happen.
Check to see where the water sprays up out of the sprayer arm at the bottom of your dishwasher. Again, you can consult the owner's manual if you're unsure. Make sure there aren't any large bowls or pans directly over the jet of water that would keep water from completely entering the dishwasher.
If soap buildup or dishes aren't preventing the detergent cup from opening, it might be a problem in the mechanics of the cup. Most modern dishwashers use a timer and wax motor to open the cup.
If you have some electrical knowledge, you can consult the owner's manual to learn how to access the timer and wax motor. Make sure that you turn off the water supply to the unit and wait for any existing water to dry up before working with electricity.
Don't have any electrical knowledge? Call a dishwasher repair technician to fix the problem. The timer and wax motor are parts you want installed properly for the washing machine to remain functional at all.